RAWALPINDI, Sept 15: The international day for the preservation of the ozone layer is being observed on Tuesday with focus on combating the depletion of the earth’s fragile protective shield.

The theme of this years “Montreal Protocol – global partnership for global benefits” is meant to celebrate the multifaceted approach pursued by the parties in the implementation of the protocol.

Ozone is a gas that occurs both in the earth’s upper atmosphere (the stratosphere) and at ground level.

Ozone can be “good” or “bad” for people’s health and the environment, depending on its location in the atmosphere.

“Good”ozone is produced naturally in the stratosphere and it blocks harmful UV radiation from reaching the earth’s surface where it can harm people and ecosystems. “Bad” ozone is an air pollutant found at ground level and it is harmful to breathe in and can damage crops, trees, and other vegetation.

UV radiation can damage sensitive crops, such as soybeans, and reduce crop yields. Some scientists believe that marine phytoplankton, which serves as the base of the ocean food chain, is already under stress from UV radiation.

This stress could have profound effects on the food chain and on food productivity.

Additionally, since most ozone-depleting substances are also potent greenhouse gases; replacing these substances with alternatives that are safer for the ozone layer can also reduce greenhouse gas emissions and slow climate change.